TB Testing

TB Skin Test

The TB skin test may be used to find out if you have TB infection. A health care worker will inject a small amount of testing fluid (called tuberculin or PPD) just under the skin on the under side of the forearm. After two or three days, you must return to have your skin test read by the health care worker. You may have a swelling where the tuberculin was injected. The health care worker will measure this swelling and tell you if your reaction to the test is positive or negative. A positive reaction usually means that you have been infected by someone with active TB disease.

If you have recently spent time with and been exposed to someone with active TB disease, your TB skin test reaction may not be positive yet. You may need a second skin test 8 to 10 weeks after the last time you spent time with the person. This is because it can take several weeks after infection for your immune system to react to the TB skin test. If your reaction to the second test is negative, you probably do not have latent TB infection.

TSPOT and Quantiferon are two blood tests used to detect TB infection using the Interferon Gamma Release Assay (IGRA) method. For more information on these products, please contact our office at (334) 206-5330.


Recommendations for Tuberculosis Screening in Students

The Alabama Department of Public Health (ADPH) and the Alabama Tuberculosis Medical Advisory Council recommend that all colleges and universities devise policies and procedures to assure that all first time students (undergraduates, graduate, transfer, English language program) are evaluated for TB prior to attending classes.

Each student who is determined to be part of an at risk population for developing TB must present the results of a TB skin test (Mantoux PPD) or blood assay for Mycobacterium tuberculosis (i.e., Quantiferon Gold or T-Spot) within two months prior to matriculation.

It is the right and responsibility of each institution to determine whether they will accept skin test results from an outside facility or require testing at an affiliated clinic.

Screening Recommendations and Risk Questionnaire for Students

  • Approved by TB Medical Advisory Council, January 30, 2009
  • Approved by State Committee of Public Health, March 18, 2009

Page last updated: August 15, 2017